Light-sensitive supersensitized silver halide color photographic emulsions

ABSTRACT

A SUPERSENSITIZED SILVER HALIDE EMULSION CONTAINING IN COMBINATION A SENSITIZING DYE OF THE FORMULA   2-((3-(HO3S-(CH2)N-),5-(PHENYL)BENZOXAZOLIN-2-YLIDENE)=   CH-C(-R1)=CH-),3-((-)O3S-(CH2)N-),5-(PHENYL)-   BENZOXAZOL-3-IUM   AND A SENSITIZING DYE OF THE FORMULA   2-((-N(+)(-R4)=Z-)&gt;C-CH=C(-R3)-CH=),3-R2,5-Y1,6-Y2-BENZ-   OXAZOLINE (X(-))(M-1)   WHEREIN THE VARIOUS SYMBOLS ARE DESCRIBED IN THE CLAIMS.

United States Patent "7' US. Cl. 96-124 Claims ABSTRACT OF THEDISCLOSURE A supersensitized silver halide emulsion containing incombination a sensitizing dye of the formula and a sensitizing dye ofthe formula N I la wherein the various symbols are described in theclaims.

This invention relates to a color photographic emulsion which issupersensitized by the use of two sensitizing dyes in combination. Moreparticularly, the invention pertains to a light-sensitive silver halidecolor photographic emulsion incorporated with at least one sensitizingdye of the general Formula A shown below in combination with at leastone sensitizing dye of the general Formula B also shown below.

GENERAL FORMULA A GENERAL FORMULA B wherein:

R is a lower alkyl group,

R is a hydrogen atom or a lower alkyl group,

R and R are independently selected from the group consisting of a loweralkyl group and alkyl substituted by a sulfonic acid, carboxylic acid orhydroxyl group,

3,580,724 Patented May 25, 1971 alkyl group As is well known,supersensitization is a means for enhancing the spectral sensitivity ofa light-sensitive photographic layer by using, in combination with themain sensitizing dye, a dye or non-dye compound different in chemicalstructure from said main sensitizing dye. Sensitizing dyes used for thesupersensitization of photographic silver halide emulsions are requiredto satisfy the following requirements:

(1) They should be high in synergistic spectral sensitizing effects andhave superadditivity.

(2) They should be proper in intended spectral sensitizing area and,particularly when used as light-sensitive color photographic materials,they should satisfy a spectral sensitivity area showing the best colorreproductivity.

(3) They should have no detrimental interactions with any otherphotographic additives used, and they should maintain stablephotographic characteristics even during storage of the resulting films.

(4) They should leave no color stains on films after development.

In view of such requirements as are mentioned above, it has heretoforebeen eifected to carry out the supersensitization in a visible spectralarea by incorporating two or more sensitizing dyes in a photographicsilver halide emulsion. However, there have been known few sensitizingdyes which can satisfy the abovementioned requirements.

The object of the present invention is to provide a light-sensitivesilver halide color photographic emulsion supersensitized by the use ofsensitizing dyes which satisfy the above-mentioned requirements and,particularly, do not bring about any deletrious effects in photographiccharacteristics such as fogging and desenitization even when they arepresent together with anionic compounds, which are gelatine-coagulants(precipitating agents) or magenta couplers.

As a result of various studies, it has been found that the above objectcan be accomplished by incorporating into a photographic silver halideemulsion at least one sensitizing dye of the aforesaid general Formula Ain combination with at least one sensitizing dye of the aforesaidgeneral Formula B. That is, the kind of sensitizing dyes, which are usedin the known sensitization processes, have such drawbacks, in the casewhere lower alkyl groups have been substituted on all the nitrogen atomsof the heterocyclic rings [eg in the cases of the control dyes (12) and(13) mentioned below], that when used together with incorporated colorcouplers, they cause an increase of fog and a decrease of colorsensitivity during storage of films to deteriorate the photographiccharacteristics of the films, in most cases. The combination ofsensitizing dyes employed in the present invention is characterized byusing, as the main dye, an oxacarbocyanine having sulfoalkyl groupssubstituted in the nitrogen atoms on the heterocyclic rings, as seen inthe aforesaid general Formula A. It has been found that by using saidcombination, there are displayed such excellent photographiccharacteristics as are mentioned above.

Typical examples of the sensitizing dyes represented by the generalFormulas A and B are enumerated below, but the sensitizing dyes usablein the present invention are by no means limited thereto.

Typical of the sensitizing dyes of the general Formula A are as follows:

(C QA Oa (CH2)4S03H CH a I (0119 50311 on2 rso3 oH-o=oH- (I! H If 2 a Ga7/ (CH2)sSOaH (01193 03 OH(|3=OH \III CzHr G91II/ (CH2)2SO3H (01192303Typical of the sensitizing dyes of the general Formula B are as follows:

=CH-C=CH (3H3 \N CH@ 1 l CzH5 CBHB =CHC=CH (3H3 CHs a crimson: camisol 0S CH3 =CH-C=CH (L1H: CH3 N N bnnlsoan cmnooo =CHC=CH- N JHa \N I 9 Cali](CHz)4SOa =OH-(IJ=CH CH3 -O CzHs N 1;] (132E: 93302 CH 0H3 =CHC=CH I C1-CH3 \N 1 9 CzHs (CH2)3S03 OH; H

-CHCH=CH e I GH3 CH3 r CzHs CH3 CH-C=CH 6 C104 CH5 I 2 CzHs CZ E CH3CH-C=CH G CZHS glf CH3 I lzHs (CH2)2OH The distribution of the maximumcolor sensitization wave lengths of the present photographic silverhalide emulsions is variable depending on the kind and amount of thesensitizing dyes represented by the aforesaid general formulas. Thesesensitizing dyes may be added to photographic silver halide emulsionsafter dissolving them together or individually in an organic solventoptionally miscible with water, such as methanol or ethanol. Further,these sensitizing dyes may be added to photographic silver halideemulsions at any time during the course of the preparation of theemulsions. Generally, however, it is preferable to add them immediatelyafter the second ripening. The amount of the dyes to be added variesdepending on the kind of silver halide emulsion. Ordinarily,

however, it is preferable to adopt such amounts that the total amount ofthe combination of the sensitizing dyes represented by the aforesaidgeneral Formulas A and B is 3020O mg. per kg. of the silver halideemulsion. In some cases, the silver halide emulsion may be sensitized.In such a case, the amount of the sensitizing dye represented by thegeneral Formula B is preferably 1-20% of the total amount.

Silver halide emulsions employed in the present invention are colorphotographic emulsions containing incorporated color couplers capable offorming magenta color dyes. Usable silver halide emulsions includesilver iodobromide, silver chlorobromide, silver bromide and silverchloride emulsions. Particularly, the use of silver iodobromide emulsionis preferable. These silver halide emulsions may have been sensitizedwith noble metal sensitizers, sulfur sensitizers, reduction sensitizersor polyalkylene oxide type sensitizers, and may have been incorporatedwith such known additives as stabilizers, surface active agents,hardeners, etc.

The present invention will be illustrated below with reference to thefollowing examples, but the examples are merely illustrative and theinvention is, of course, not limited thereto.

EXAMPLE 1 To 1 kg. of a neutral, high speed sensitivity silveriodobromide emulsion containing 5 mol percent of silver iodide,immediately after completion of the second ripening according to thegold or sulfur sensitization process, were added sensitizing dyes of thegeneral Formulas A and B, either singly or in combination, in the formof 0.1% methanol solutions in the amounts as set forth in Table 1.

After completion of the ripening, to the mixture was added 300 mg. of4-hydroxy-6-methyl-1,3,3a-7-tetrazaindene as a stabilizer and was thendispersed and mixed according to an ordinary procedure with1-(4-phenoxy-3- sulfophenyl)-3-heptadecyl-5-pyazolone as a colorcoupler, and the mixture was adjusted to pH 6.8 to prepare a greenlight-sensitive color photographic emulsion.

The thus obtained emulsion was uniformly coated on a cellulosetriacetate film support and was then dried to prepare a sample. Thesample was exposed to 160 Lux daylight (5400 K.) through a green filterhaving a maximum transmission of 525 m from a Model KS-l sensitometer(manufactured by Konishiroku Photo Industry Co., Ltd., Japan) and wasthen subjected to color development at 20 C. for minutes, using a colordeveloper of the following composition:

G. N,N-diethyl-p-phenylenediamine sulfate 2.5 Anhydrous sodium sulfite2.0 Sodium carbonate (monohydrate) 82.0 Potassium bromide 2.0

Water to make 1 1.

After the development, the sample was subjected to ordinary bleaching,fixing and water-washing treatments, and was measured in fog and greenlight sensitivity to obtain the results as shown in Table 1. Thesensitivity value in the table is represented by the relative greenlight sensitivity of the sample as measured by assuming that the greenlight sensitivity attained by the independent use of the dye (3) is 100.

TABLE 1 sensitizing dye (0.1% methanol solution, 00.] kg. emulsion)Relative Sensi- Sensitizmg sensitizing speed for tivity dye exemplidyeexempligreen maximum fiedby (3),ce. fied by (8), cc. Fog light (my) Thethus prepared emulsions were immediately coated individually on thecellulose triacetate film support and were then dried to prepare freshsamples. Separately, the emulsions were incubated at 40 C. for 3 hoursand then treated in the same manner as above to prepare other samples.These samples were exposed and color developed in the same manner as inExample 1 and were then subjected to sensitometry to obtain the resultsset forth in Table 2.

The sensitivity value in the table represents the relative sensitivityof each sample as measured by assuming that the green light sensitivityof the fresh control sample is 100.

TABLE 2 Ineubated at 40 C. for

Immediately after the 3 hours after the preparation of emulsionpreparation Relative Relative green light green light sensitizing dye(0.1% methanol solution, ce./kg. emulsion) sensitivity Fog sensitivityFog Dye exemplified by (1): Dye exemplified by (5):

40 00 3 cc 0. 07 0. 08 60 0e 5 cc 0. 12 120 0. 13

Dye exemplified by (2) Dye exemplified by (5):

10 ee 3 cc 120 0. 08 125 0. 08 60 cc 50c; 0. 13 0. 14

Dye exemplified by (2): Dye exemplified by (11):

40 cc cc 125 0. 08 130 0. 09 60 cc 5 cc 135 0. 15 130 0. 17

Control dye (14): 60 cc Control dye (15): 5 cc 100 0. 21 94 0. 28

As shown in Table 1, it is clear that if the dyes are used incombination in accordance with the present invention, the green lightsensitivity is greatly enhanced as compared with the case where they areused independently.

EXAMPLE 2 The same high speed silver iodobromide emulsion as in Example1 was divided into several portions. To each portion of the emulsion,0.1% methanol solutions of combinations of the present sensitizing dyesrepresented by the aforesaid general Formulas A and B were individ-EXAMPLE 3 The same high speed silver iodobromide emulsion as in Example1 was divided into several portions. To each 5 portion of the emulsion,combinations of 0.1% methanol solutions of the present sensitizing dyesrepresented by the general Formulas A and B were individually added inamounts shown in the Table 3 per kg. of the emulsion.

On the other hand, l-(2,4,6-trichlorophenyl)-3-[3- (2,4- ditert.-amyl-phenxyacetamide) benzamide1-5-pyrazolone was dissolved byheating in a mixture of di-n-butyl phthalate and ethyl acetate, and wasdispersed in a gelatine solution with the use of sodiumalkylbenzenesulfonate. The thus formed dispersion was added to eachemulsion. Subsequently, the mixture was adjusted to pH 6.8 to prepare agreen light-sensitive emulsion. Separately, the dyes (l4) and (15employed in Example 2 were treated in the same manner as above toprepare a control emul- SlOIl.

The thus prepared samples were immediately coated individually on a filmbase and were then dried to prepare samples. The samples -were exposedin the same manner as in Example 1 and were color developed at 21 C. for10 minutes the use of a color developer of the following composition:

N-ethyl-N-B-methanesulfonamidoethyl-3-methylaminoaniline sulfate2.5 g.

Anhydrous sodium sulfite-2.0 g.

Benzy alcohol-18 ml.

Sodium hexamethaphosphate--2.0 g.

Sodium carbonate (monohydrate)-5 0.0 g.

Potassium bromide-1.0 g.

Caustic soda-06 g.

Water to make-l 1.

-After the development, the samples were subjected to ordinarybleaching, fixing and water-washing treatments, and were measured in fogand green light-sensitivity to obtain the results shown in Table 3. Thesensitivity value in the table represents the relative sensitivity ofeach sample as measured by assuming that the green light sensitivity ofa combination of the control dyes is 100.

8 a second ripening according to a goldor sulfur-sensitization method.Immediately before completion of the ripening, the emulsion was dividedinto several portions. To each portion of the emulsion, 0.1% methanolsolutions of the present sensitizing dyes represented by the generalFormulas A and B were individually added in the amounts shown in Table 4per kg. of the emulsion. After completion of the ripening, each mixturewas charged with an optimum amount of a stabilizer and was then mixedaccording to a known procedure with 1 (3-carboxyphenyl) 3(4-stearoylaminophenyl)-5-pyrazolone as a magenta coupler, and themixture was adjusted to pH 6.8 to prepare a green light-sensitive,reversal color photographic emulsion. The thus obtained emulsions wereuniformly coated individually on a cellulose triacetate film support toprepare samples. Further, there were also prepared stored samples insuch a manner that the samples were individually stored for 3 hours at atemperature of 55 C. and for 3 days at a temperature of 50 C. and

a humidity of 50%.

Subsequently, the samples were exposed in the same manner as in Example1 and were developed at 20 C. for 10 minutes with a developer of thefollowing composition:

v G. Monomethyl-p-aminophenol sulfate 3 Anhydrous sodium sulfite 50Hydroquinone 6 Sodium carbonate (monohydrate) 50 Potassium bromide 1Water to make 1 1.

TABLE 3 Relative green light sensitizing dye (0.1% methanol solution,cc./kg. emulsion) sensitivity Fog Dye exemplified by (3): Dyeexemplified by (12):

cc 2.5 cc- 130 0. 10 50 cc 120 0. l2

Dye exemplified by (1): Dye exemplified by (9):

50 cc 2. cc 125 0.07 50 cc 140 0. 08

Control dye (14):

50 cc 95 0. 1s 50 cc 100 0.20

From Table 3, it is seen that even in the presence of G lipophilicinternal couplers, the photographic silver halideN,N-diethyl-p-phenylenediamine sulfate 5 emulsions in accordance withthe present invention have Anhydrous sodium sulfite 2 excellent greenlight sensitivity less in fog as Compared Sodium carbonate (monohydrate)82 with the conventional emulsion. P t i b id 1 EXAMPLE 4 Reversal colorphotographic silver iodobromide emulsion containing 3 mol percent ofsilver iodide which had been treated with a gelatine coagulant (sodiumnaphtha- Water to make 1 1.

lene-sulfonate-formaldehyde condensate) was subjected to dried.

The thus treated samples were measured in sensitivity and fog (residualcolor density) to obtain the results shown in Table 4. The sensitivityvalue in the table is the relative sensitivity of each sample asmeasured by assuming that the green light sensitivity of the controlsample is 100.

TABLE 4 Ineubated samples Ineubated at 55 C. Ineubated at; 50 C.

for 3 days and 80% relative Fresh sample humidity for 3 days RelativeRelative Relative green light green light green light sensitizing dye(0.1% methanol solution, (xx/kg. emulsion) sensitivity Fog l sensitivityFog 1 sensitivity Fog 1 Dye exemplified by (3), 60 (20-. Dye exemplifiedby (7), 3 cc 140 0. 14 135 0. 15 135 0. 15

Dye exemplified by (3), 130 cc Dye exemplified by (5) 9 cc 155 0. 16 1500.17 145 0.16

Dye exemplified by (l), 130 cc. Dye exemplified by (10), 9 cc 125 0. 13120 O. 14 115 0. 13

Control dye (14), 130 cc Control dye (15), 9 cc 100 0. 21 90 0. 22 750.21

1 Residual color density.

As is clear from Table 4 the light-sensitive photographic silver halideemulsions of the present invention are high in green light sensitivityof magenta coupler layer and less in residual color density as comparedwith the control sample [control dye (14) control dye (15)] and thatthey are not decreased in color sensitivity even when subjected tosevere storage tests.

What we claim is:

1. A light-sensitive silver halide color photographic emulsion whichcontains at least one sensitizing dye of the general 'Formula A shownbelow in combination with at least one sensitizing dye of the generalFormula B shown below:

C=CHC=CHC a R is a lower alkyl group,

Y is a hydrogen atom or a methyl group with the proviso that Y is amethyl group when Y is a chlorine atom, or

Y and Y may form a benzene ring,

Z is a group necessary to form a thiazole, thiazoline, benzothiazole orbenzoselenazole ring, or an alkyl or alkoxy derivative thereof,

X is an acid anion,

n is an integer of 2 to 4, and

m is l or 2.

2. A light-sensitive silver halide color photographic emulsion asclaimed in claim 1, further containing a magenta color coupler.

3 A light-sensitive silver halide color photographic emulsion as claimedin claim 1, wherein said emulsion has been sensitized by way of noblemetal sensitizers, sulfur sensitizers, reduction sensitizers orpolyalkylene oxide type sensitizers.

4. A light-sensitive silver halide color photographic emulsion asclaimed in claim 1, further including stabilizers, surface activeagents, coating aids or hardeners.

5. -A light-sensitive silver halide color photographic element whichcomprises a film support and, coated thereon, a layer of the emulsion asclaimed in claim 1.

References Cited UNITED STATES PATENTS 2,680,686 6/1954 Van Dormael etal. 96-104 J. TRAVIS BROWN, Primary Examiner

